最新刊期
卷 28 ， 期 6 ， 2000
- 摘要：In distributed fusion system,the problem that sensors of the system are of different type is a widespread problem.In this paper,from the process of hierarchical fusion,a resolution of fusion state definition,dimension extension of filter state vector from a single sensor as well as its covariance matrix,trace fusion and prediction after extension is introduced,followed by the essence of such kind of problem.关键词：track fusion;hierarchial fusion;Kalman filtering;RHV mode;jerk mode;dimension extention algorithm0|2|1更新时间：2025-07-02
- 摘要：Based on the space-time eigenstructure of signals,a novel space-time DOA matrix method is proposed to estimate the high-resolution 2-D DOA of narrowband signals.The method transfers the observed data from space domain to 2-D space-time domain by exploiting the cross-correlation of the array outputs,and a large amount of virtual elements are generated through space-time processing.Therefore the constraint over the array configuration and the element identity can be significantly weakened,which means the matching subarray is no longer needed and the advantage of the traditional DOA matrix method,such as automatical parameter alignment and no need of 2-D search,is still available.The simulation results show the effectiveness of the method.关键词：antenna array;smart antenna;DOA;space-time processing4|4|8更新时间：2025-07-02
- 摘要：An optimal tracking gate algorithm based on the performance of data association is presented in this paper.The invalid measurements are reduced effectively by using it and this leads to improve the performance of Multitarget-Multisensor tracking system.The analyses of theory and the result show that the performance of algorithm is improved over the classical method,especially in a multitarget heavy clutter and false alarm environment.关键词：multitarget tracking;data association;tracking gate;optimal algorithm1|2|52更新时间：2025-07-02
- 摘要：A robuster algorithm for beamforming is presented in this paper,which is based on the Eigenspace-Based Algorithm for adaptive beamforming.By utilizing the signal subspace obtained with the eigenstructure of the correlation matrix,the constrained steer vector is calibrated in the ESB Algorithm.Computer simulation and analysis demonstrate the performance excess of the proposed algorithm over the conventional ESB Algorithm.关键词：adaptive beamforming;array signal;eigenspace0|2|7更新时间：2025-07-02
- 摘要：Fractal coding has been proved useful for image compression.It is also proved effective for content-based image retrieval.In the paper,we present a block-constrained fractal coding scheme and a matching strategy for content-based image retrieval.In this coding scheme,an image is partitioned into non-overlap blocks of a size close to that of a query iconic image.Fractal codes are generated for each block independently.In the similarity measure of fractal codes,an improved nona-tree decomposition scheme is adopted to avoid matching the fractal codes globally in order to reduce computational complexity.Our experimental results show that our coding scheme and the matching strategy we adopted is useful for image retrieval,and is compared favorably with other two methods tested in terms of storage usage and computing time.关键词：fractal coding;image coding;iterated function systems (IFS);content-based image retrieval0|2|9更新时间：2025-07-02
- 摘要：Inverse synthetic aperture radar (ISAR) imaging of the non-cooperative maneuvering target is a challenging task due to its time-varying orientation and rotation velocity which denies accurate measuring.This paper investigates the general principles of ISAR imaging of maneuvering targets,and proposes an algorithm for application in situations when the maneuverability is not too serious and the Doppler variation of sub-echoes from scatterers can be approximated as a first order polynomial.The imaging results using real data show the effectiveness of the new method.关键词：inverse synthetic aperture radar(ISAR);maneuvering target;LFM signal0|2|14更新时间：2025-07-02
- 摘要：There are a great varitety of applications of tracking human faces in head-shoulder sequences.However,most tracking algorithms,so far,are unable to meet the demands for both precise and fast tracking.A real-time algorithm,based on organ tracking,for tracking human faces in head-shoulder sequences is presented in this paper.The algorithm implements tracking the human face by tracking the mouth with morphology,then analyzing the symmetry of the face.The simplicity of morphological and the local rotating operations enable real-time tracking.Meanwhile,the analysis of the symmetry of the face guarantees precise tracking.关键词：human face tracking;organ tracking;morphology0|2|9更新时间：2025-07-02
- 摘要：In this paper,an approach of the XYZ video compression based on 3-D DCT is considered.This method does not involve motion estimation and motion compensation,thus the computational complexity is low.Experimental results show that this algorithm which is able to compress video rapidly and effectively is a video coding method with great potentials.关键词：video coding;3-D discrete cosine transform;zigzag scanning0|2|11更新时间：2025-07-02
- 摘要：This paper gives a method of image edge detection,using multiple edge features and fuzzy reasoning.To effectively extract edges,edge pixels are classified according to the difference of intensity distribution,and multiple effective edge features are defined.Edges are detected by applying fuzzy reasoning (min-max centriod method),based on local image edge characteristics.Finally,the given algorithm is tested on several images.Comparison is made with standard edge detection techniques.关键词：multiple edge features;fuzzy reasoning;edge detection0|2|3更新时间：2025-07-02
- 摘要：This paper analyzed the special characteristics of impulse signal SAR in the process of imaging.In condition of sending,receiving UWB signal with big accumulating angle,the formulation of azimuth resolution was deduced.At last it was proved to be correct by the simulation results.关键词：UWB radar;impulse radar;synthetic aperture radar;azimuth resolution;back projection0|2|4更新时间：2025-07-02
- 摘要：In ISAR image technique,the rotation angle of the object is required to remove the phenomena of the migration through resolution cell and scale the cross range of the image.In this paper,a novel method for estimating the rotation angle is proposed.The core idea of this method is to use the Radon-ambiguity transform (RAT) technique to estimate the FM rate of the multiple linear frequency modulated signals in different range cells.Then,the rotation angle can be obtained from the FM rate easily.The effectiveness of the method is confirmed by the simulation and the experimental results.关键词：inverse synthetic aperture radar(ISAR);rotation angle estimation;radon-ambiguity transform (RAT);linear frequency modulated signal0|2|5更新时间：2025-07-02
- 摘要：Based on the observation that sinusoids show themselves as outliers in frequency domain,this paper proposes a new approach for the superresolution frequency estimation of sinusoids in an unknown colored noise environment by utilizing the capability of running median filters to remove outliers from data.The outstanding advantages of the method are its strong adaptability to various noise distributions and the simplicity of its implementing algorithm.Simulations are provided to show its performances.关键词：signal processing;frequency estimate;colored noise;nonlinear filtering0|2|14更新时间：2025-07-02
- 摘要：Many signal processing algorithms aim at complex signals,so it is important to create complex signal from the bandpass real signal.Intermediate frequency sampling technique samples the intermediate frequency signal directly and produces complex signal by digital signal processing.Unlike current IF sampling method,the bandwidth of the sampling filter proposed in this paper is variable,and the coefficients of the filter are given analytically.The new filter produces similar results when the sampling rate is 2b or 4b,and works much better when the band of the signal is narrow.关键词：IF sampling;digital filter0|2|3更新时间：2025-07-02
- 摘要：A temporal spatial joint processing technique to cancel cochannel interference is proposed in this paper.The inertference with direction apart from the user is suppressed by smart antenna,and the resident interference can be cancelled by a multiuser detection system.In a heavy interference channel,the proposed system can achieve better performance.关键词：CDMA;smart antenna;multiuser detection;temporal spatial joint procession0|2|5更新时间：2025-07-02
- 摘要：The effects of different parameters of step frequency waveform are discussed.Two target's redundance removed algorithms are advanced. The characteristics of these algorithms are analyzed and some expressions are given.The results of computer simulations are given.A pragmatic radar system is introduced.The results of these algorithms are in agreement with the theories in this system.关键词：radar;signal;range high resolution;step frequency;redundance0|2|1更新时间：2025-07-02
- 摘要：This paper addresses the convergence property of higher-order ambiguity function (HAF),which is used to estimate the parameters of polynomial-phase signal (PPS).For time-varying amplitude PPS in white complex Gaussian noise,the strong convergence of estimates of HAF and the highest order polynomial plase coefficient is proved.Specifically,the convergence rate of coefficient estimate is obtained in constant amplitude case.Simulations are performed to verify the theoretical results.关键词：polynomial-phase signal;higher-order ambiguity function;sample estimate;strong covergence0|2|29更新时间：2025-07-02
- 摘要：The paper focuses on the physical link simulations of WCDMA system after reviewed the candidates of 3G in detail.We have used Cossap to develop the complete library of the functions about WCDMA independently.The downlink and uplink simulation platform of physical voice and data services channel are established,and tested according to the multipath fading environments of ITU-R M.1225,WCDMA specification of ETSI in 1998 August and IMT-2000 radio interface technique specification in 1999 December.关键词：WCDMA;3GPP;Turbo code;system simulation0|2|0更新时间：2025-07-02
- 摘要：The complex environment is an important factor to restrict the radar performance,especially the airborne radar.It is also a key problem to be considered in the design of communication systems.The distribution characteristics of atomspheric structure in the troposphere with time and zones in China are analyzed.The evolution features of the surfaces of the terrain and sea with space and time are described with the fractal theory of nonlinear dynamics,and propagation effects of different atmospheric sections and rough surfaces of the terrain and sea are studied with the Fourier split-step method to solve the parabolic equation.关键词：parabolic equation;atmosphere;rough surface;fractal theory;radar;communication;radiowave propagation0|2|9更新时间：2025-07-02
- 摘要：In this paper,the 3-Dimensional scattering problem of dielectric periodic structures for the general case of oblique incidence is rigorously solved based on the analysis of the corresponding 2-Dimensional scattering problem for the special case where a plane wave is incident in the principal-plane.A method is used in the analysis,which combines the rigorous mode matching method with the multimode network approach.The guidelines for the analysis and design of the related dielectric periodic structures in the millimeter wave and optical-integrated circuits are thus given.关键词：dielectric periodic sturcture;scattering;oblique incidence;multimode network approach;rigorous mode matching method0|2|0更新时间：2025-07-02
- 摘要：The neural network model of E-plane septum is established and is used to take the place of the analysis program of design procedure of the E-plane filter.Since the neural network model has good precision and effectiveness,the deign method developed by this paper is fast and accurate.An 8mm E-plane filter is designed by the developed method and the experimental results are obtained to demonstrate the effectiveness of the developed method.关键词：neural network;BP algorithm;E-plane septum;E-plane filter0|2|1更新时间：2025-07-02
- 摘要：Leaky-wave characteristics of a class of NRD-guides with arbitrary cross section are systematically studied for their potential applications as low-cost millimeter-wave antenna.A numerical technique is applied to model these irregular structures,which is formulated by combining effectively a multimode network theory with a mode-matching method.Our emphasis is laid on the investigation of parametric effects on leakage properties of the NRD-guide.Extensive results are presented to derive some useful guidelines for the design of the new types of NRD-guide leaky-wave antennas.关键词：leaky-wave antenna;NRD guide1|2|1更新时间：2025-07-02
- 摘要：A new technique which combines the general network formulation and the connection algorithm is proposed to deal with the complex aperture coupling problems.First,the interior cavity of the aperture is divided into proper sections and the generalized admittance matrix of each section is computed by the boundary element method.Using the connection algorithm,the interior admittance matrix of the aperture can be derived by cascading the admittance matrices of individual sections.Then the aperture equivalent magnetic currents,the backscattered field and the transmitted field can be obtained by the generalized network formulation.The proposed method not only greatly alleviates computational constraints for the problem but also simplifies the analysis of apertures with complex materials inside.关键词：aperture;general network formulation;boundary element method;connection algorithm0|2|1更新时间：2025-07-02
- 摘要：The impedance and radiation characteristics of an ultra-wide band planar horn antenna are analyzed theoretically and calculated using FDTD method in this paper.This horn antenna is characterized with U-balun,simple construction and perfect performance.Perfectly Matched Layer(PML) technique is applied as absorbing boundary conditions,and Contour-Path Method (CP) is used to conform to the curved slot between the two ridges in FDTD simulation.Good agreements between calculated and measured results are obtained.关键词：ultra-wide band;antenna;FDTD method0|2|4更新时间：2025-07-02
- 摘要：A new regeneratively latched comparator is studied in the paper.Problems related to comparator failure,optimization between speed and power consumption and clock kickback effect are reviewed in order to improve the performance of the comparator.The proposed comparator has performance improvements such as a high input resistance,a less punishment from the clock kickback effect and a frequency bandwidth compensation of the preamplifier stage.Based on this,it has been integrated in a new high-speed A/D converter with a kind of normal bipolar technology.Both the performance analyses and the simulation results with the tool of PSPICE of the comparator are provided in detail.关键词：latched comparator;A/D Converter;flip-flop0|2|0更新时间：2025-07-02
- 摘要：The self-consistent nonlinear theory of relativistic backward wave oscillator with End-reflections,asynchronous interaction of the forward fundamental wave with election beam and electron beam space charge effect was built up in the conditions of classical phase mould.The Fortran code to numerically solve the nonlinear beam-wave interaction equations was constructed by use of Four-order Runga-Kutta method.The code was used to investigate the nonlinear beam-wave interaction and other optimization issues of relativistic backward wave oscillator.The numerical simulation results show:the efficiency of the uniform coupling impedance device can be up to 27% when the phase difference between the forward fundamental wave and the synchronous harmonic at the start of slow wave structure and the asynchronous beam-wave interaction are both in optimal conditions,for the device with a single step change in coupling impedance,the optimum efficiency can be up to 50%.关键词：relativistic backward wave oscillator;nonlinear theory;beam-wave interaction theory;numerical modeling0|2|2更新时间：2025-07-02
- 摘要：According to the requirements for the gyrotrons,the relativistic effect and the space charge effect were taken into account,and a set of large program is developed for CAD.The shape of electrodes,electron trajectory and electron beam parameters are given by the computer aided design.The electron gun has some advantages such as small velocity spread,good laminar flow and small volume etc..关键词：gyrotron;electron beam;electron gun;electrode shapes;numerical calculation0|2|0更新时间：2025-07-02
- 摘要：According to the design of 3mm-wave radar,an amplifier-chain scheme of the coherent pulsed transmitter is proposed.The chain consists of a fundamental injection-locked harmonic Gunn oscillator,a CW IMPATT oscillator and two pulsed IMPATT oscillators in cascade.In order to overcome the effect of the leak signal in the system,a new technique of suppressing the leak in the intervals of pulse by altering the frequency is created and realized in success.The developed transmitter provides the output of 5W peak power and 30ns pulse-width in 3mm-wave with the input of 2mW signal in 6mm-wave.关键词：millimeter wave;coherent pulsed transmitter;injection-locked;IMPATT;leak0|2|1更新时间：2025-07-02
- 摘要：A new method for sinusoidal detection is presented based on the SVD of the observation data matrix.Compared with general approach,the method here can be used to deal with the observation data merged in noise background and to analyze short data record.The method in this paper has fairly computational stabilization and can eliminate the noise mixed in the sinusoidal observation data to obtain exact results.The validity and the correctness of the new approach are verified by the computer emulation.关键词：harmonic progress;sinusoidal detection;singular value decomposition;least square method0|2|16更新时间：2025-07-02
- 摘要：Multiple access interference (MAI) is one of the major impairments on the performance of CDMA systems.On the basis of decision feedback theory we propose a new blind adaptive multiuser detector with variable step size for canceling interference.Theoretical analysis and numerical simulation show that the convergence performance and symbol error performance of the new algorithm are better than those of the MOE detector.关键词：CDMA;MAI;blind equalization;adaptive interference cancellation0|2|8更新时间：2025-07-02
- 摘要：This paper presents an analysis of the effect of the amplitude and phase perturbation (modeling error) on the performance of the MUSIC algorithm.The theorectical expression of the statistical spatial spectrum for the case of modeling error existing in the system is derived.The theoretical analysis reveals the relationship between the error of spectrum and the variance of perturbation.The theoretical prediction is validated by computer simulating.The amplitude and phase perturbation decrease the peak values of spectrum and lower the resolution power.The results are of great significance to the array designer.关键词：spatial spectrum;super-resolution;error analysis0|2|0更新时间：2025-07-02
- 摘要：A novel method of motion estimation based on an improved genetic algorithm is presented.By applying a threshold selection operator and combining objective search with random search derived from genetic mutation,the method can overcome the shortcoming of being liable to local optimum,thus the estimation speed is prompted.The performance of search is also improved by selecting the initial population based on the coherence rule within the motion vector space.The inherent regularity and high parallelism of genetic algorithm make it feasible for VLSI implementation of video encoders.关键词：motion estimation;block matching algorithm;genetic algorithm0|2|0更新时间：2025-07-02
- 摘要：From the point of view of the space-time adaptive processing,the principle and realization of modern airborne Displaced Phase Center Antenna (DPCA) techniques are researched in this paper,which include two-element DPCA,multiple phase centers DPCA,multiple phase centers-cascade DPCA,∑-Δ DPCA and frequency domain DPCA.Moreover,when the DPCA condition is not satisfied,the clutter suppression performance of DPCA is analyzed in detail.关键词：airborne radar;clutter rejection;DPCA;space time adaptive processing0|2|16更新时间：2025-07-02
- 摘要：By combining the corresponding detail subimage data of the still image and text watermark when they are decomposed into subimages of different resolution level with wavelet transform,the paper proposed a scheme for still image text watermark in which the watermark embedding process employs the human visual masking model.With resorting to the original image,it is easy and reliable to extract the text watermark.Moreover,the experimental results show that the embedding text watermark is robust enough to image degradation processes.关键词：wavelet transform;data combination;text watermark0|2|0更新时间：2025-07-02
- 摘要：In a MPEG-2 system.it is a key technique to obtain perfect timing model for decoding Systems、Video and Audio.In this timing model,the end-to-end delay between the signal input to an encoder and the signal output from a decoder should be a constant .According to the MPEG-2 International Standard,the whole software and hardware solution of the timing model including encoder、multiplexer、remutiplexer and decodr which have constant delay is presented.关键词：MPEG-2;constant delay;encoder;multiplexer;decoder0|2|0更新时间：2025-07-02
- 摘要：CDMA CCSDA(Code Channel Space Dynamic Allocation Based on Distributed Antennas) is presented in this paper,which has multiple antennas that are divided into a number of groups.So,the area served by a base station are splited into numerorous sub-cells.A Switch/Weightingsum Mixer module is used to allocate user-specific signal to any antenna group in the base atation.CDMA-CCSDA can reduce interference and increase capacity significantly because of its unique structure.关键词：code channel space dynamic allocation;distributed antennas;CDMA;mobile communications system0|2|2更新时间：2025-07-02
- 摘要：This paper mainly deals with the problems raised in tumor hyperthermia,with only a few measured temperatures to carry out the parameter identification for reconstruction temperature fields.In order to get the solutions to the optimal identification of the tumor blood perfusion parameter which plays an very important role in bio-heat transfer,this paper proposes firstly the method of applying genetic algorithm to implement the progress of parameter identification of the tumor blood perfusion.By using this genetic algorithm method,the high precision results of global optimal parameter identification of the tumor blood perfusion parameters are performed and automatically matched the model.At the same time,the genetic algorithm method applying to nonlinear parameter identification in bio-heat transfer has a great meaning in control problem of the same kinds.关键词：hyperthermia;genetic algorithm;parameter identification;global optimal0|2|0更新时间：2025-07-02
- 摘要：A hybrid method is prposed for the optimization of multisensor detection system under Neyman-Pearson criteria.It optimizes the object function by using evolutionary strategies to do global search and Powell's directional acceleration method to do local search respectively,and does not need the object function's derivation information.The results of distributed CFAR system design examples show better convergent ability and precision for the hybrid method than gradient algorithm.关键词：multisensor detection;Neyman-Pearson criteria;evolutionary strategies;Powell's directional acceleration method0|2|3更新时间：2025-07-02
- 摘要：In this paper we present a new iteration method,namely,the variational Born iteration method (VBIM) to inverse the formation conductivity using measurement data from the array induction tool (AIT).Based on nonlinear integral equation,the inversion equation is derived by using the variational principle.In each iteration of VBIM,a numerical mode-matching method (NMM) is used to solve the logging responses of the AIT.Numerical simulation has shown that this method is easier than the DBIM.The inversion results are in agreement with the true conductivity profile by using multi-information of array on the axis of the borehole.关键词：inverse scattering;variational Born iteration method;array induction tool;multi-information of array;geophysical well logging0|2|6更新时间：2025-07-02
- 摘要：The RCS of an arbitrarily shaped cavity with a complex termination is analyzed in this paper by using GRE-FDTD hybrid method.A new ray-tracing method based on the discrete modeling of cavity is presented.The 2D results confirm the reality of this method.关键词：complex termination;cavity with slowly varying shape;radar cross section;generalized ray expansion method;finite difference time domain method;ray tracing0|2|5更新时间：2025-07-02
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